In general, a vehicle such as an automobile has mounted thereto a wiper device provided with a washer nozzle for washing liquid injection for the purpose of removing raindrop or washing out stains on a windshield. The washer nozzle is fitted to a front engine hood of the vehicle or a front hood thereof, and washing liquid is injected, at a predetermined timing, from the engine hood toward a window glass. The washing liquid is injected within a wiping area. However, not all the washing liquid is injected within the wiping area, but a part of the washing liquid may be injected to an unnecessary area outside the wiping area. Thus, in a conventional wiper device, excessive washing liquid is injected from the washer nozzle to a glass surface, deteriorating use efficiency of the washing liquid. Further, a large distance between the injection port of the washer nozzle and window glass easily causes displacement of an injection point due to wind pressure at high-speed running.
In recent years, as a countermeasure against the deterioration in use efficiency of the washing liquid or displacement of the injection point, there is proposed a wiper device in which an injection port or an injection nozzle (hereinafter, collectively referred to as “injection nozzle”) is provided in a wiper blade itself. In such a wiper device, a water channel for the washing liquid and an injection nozzle are formed inside the blade. The wiper blade is connected with a water supply tube (water supply line) extending from a washing liquid tank. The water supply tube extends along a wiper arm and is connected to the wiper blade at a connection portion between the wiper arm and wiper blade. The washing liquid is injected from the injection nozzle formed in the wiper blade onto a window glass. At the time of wiping and washing, the washing liquid is supplied from a position extremely near a glass surface and is thus used efficiently. An increase in the use efficiency of the washing liquid leads to a size reduction of the washing liquid tank, which can in turn reduce a size and a weight of the vehicle.    Patent Document 1: Jpn. UM Appln. Laid-Open Publication No. S62-28662